Control device for material distributing hopper



Jan. 15, 1957 R. J. MILLER ETAL CONIRCL-DEVICE FOR MATERIAL DISTRIBUTING HOPPER 2 Shets-Sheet 1 Filed Feb. '1, 1951 INVENTORS c4 flREA'CE a. PIC/Ii) Jan. 15, 1957 R. J. MILLER ETAL 2,777,733

CONTROL DEVICE FOR MATERILAL. DISTRIBU'IPING HOPPER Filed Feb. 7, l951 2 Sheets-Sheet 2 karma/v0 .1 114/415? United States Patent p CONTROL DEVICE FOR MATERIAL DISTRIBUTING HQPiPER Raymond E. Miller, Detroit, and Clarence B. Rickey, Royal Oak, Mich, assignors, by mesne assignment to ord Motor Company, Dearborn, Welt, a corporation of Delaware Application February 7, 1951, derial No. 209,725

3 Claims. c1. 29s--z0 This invention relates to an improved device for controlling the rate of movement of the piston of a hydraulic cylinder.

in preparing soil for crops of various sorts, there is usually deposited on the ground either before or after plowing, a measured amount of fertilizer, lime, or other soil renovating materials. Many types of spreading devices have been heretofore employed to distiibute such material and most all of such devices utilize some sort of echanical arrangement for measuring and dispensing the material being distributed on the ground. Most of these devices are ground driven by the spreading device. While perhaps a large number of these measuring devices are relatively accurate, the spreading devices heretofore known have all utilized various forms of apertures or nozzles to discharge the fertilizer which are prone to clog at the least provocation; hence regardless of the accuracy of the measuring device, the material dispensing machine is hampered in the proper distribution of the material by the clogging of such machines.

In order to eliminate such clogging of the distribution mechanism of the material distributor, other types of machines have been developed which utilize a substantially difierent concept in the distribution of the material. One such machine is described and claimed in the copending application of Clarence B. Ru'chey filed February 8, 1951, Serial No. 209,933 and assigned to the assignee of this application. This machine incorporates a swinging or rotary hopper from the top of which the fertilizer is removed by an endless belt. The hopper is raised upwardly against the continuously moving belt by a suitable drive echanism generally powered by the wheels of the material distributor. Unfortunately, however, the various mechanical feeding arrangements for incrementally rotating the hopper to insure that the belt will be in constant engagement with the material to be distributed were far from satisfactory.

It has been noted too that in distributing fertilizer or lime on a field, many distributors do not deliver a con stant rate of application of such material over the ground traversed. This is especially noticeable when the speed of the distributor is accelerated or decelerated such as when going down a slope or up an incline. Unfoltunately the feeding mechanism of such distributors were not capable of adjusting themselves to variations in the ground speed with suflicient accuracy to insure a uniform rate of delivery of the material on the ground. Another drawback was the inability to vary the rate of delivery of the material over a wide range.

Accordingly, it is an object of this invention to provide an improved control device including a hydraulically operated piston for controlling the movement of a pivoted hopper of a material distributing implement.

Another object of this invention is to provide a control device for a hydraulically operated piston which has an infinite number of adjustments to provide any desired increment of movement of the piston as a function of the speed of rotation of a control or reference member.

2,777,733 Patented Jan. 15, 1957 A further object of this invention is to provide a control device for a hydraulically operated piston which is positive and highly accurate in operation and yet which 18 relatively simple and inexpensive to manufacture.

Another object of this invention is to provide an hydraulic control device for a material distributor wherein the rate of delivery of the material to be distributed is maintained constant regardless of the ground speed of the material distributor.

Still another object of this invention is to provide a control device for a material distributor which permits an infinite variety of settings for delivering an infinitely variable amount of material per unit of area traversed by the distributor.

Another object of this invention is to provide a control for an implement carried ram actuated by the ground Wheels of the implement for supplying pressured fluid to the ram to control the movement of the ram as a function of ground speed.

The specific nature of this invention, as well as other objects and advantages thereof, will become apparent to those skilled in the art from the following detailed description, taken in conjunction with the attached sheets of drawings on which, by way of preferred example only, is illustrated one embodiment of this invention.

On the drawings:

Fig. 1 is a plan view of a material distributing device incorporating the hydraulic ram of this invention and control therefor.

Fig. 2 is an enlarged sectional view taken along the plane 22 of Fig. 1.

Fig. 3 is an enlarged longitudinal sectional view of the hydraulic ram and control device of this invention.

Fig. 4 is a sectional view taken along the plane 44 of Fig. 3.

Fig. 5 is an enlarged left end elevational view of the control device shown in Fig. 3.

Fig. 6 is a cross sectional view taken along the plane 6-6 of Fig. 3.

Fig. 7 is an enlarged fi-agmentary detail sectional view of the pump regulator.

As shown on the drawings:

Briefly this invention comprises a hydraulic ram mounted in a cylinder housing and associated therewith is a power driven pump for supplying pressured fluid to the cylinder for moving the ram. A control mechanism is associated with the pump for controlling the amount of pressured fluid delivered to the hydraulic ram as a function of the rotation of a controlling or reference element, and such control device may be readily adjusted to provide an infinite number of settings, whereby the rate of travel of the hydraulic ram may be varied to provide any desired relationship to the rate of movement of the controlling element.

The control device of this invention obviously has wide application, being usable wherever a controlled rate of feed or movement of a certain element of a machine or implement is desired as a function of the rotation of a controlling element; however, for purposes of illustration, such device will be described in connection with its application to a material distributing machine or implement 11? wherein the ground wheels of such implement function as the controlling element. Inasmuch as the particular material distributor 16 forms no part of this invention and is fully described in the above-mentioned copending application, such implement will be here described but briefly.

Such distributor comprises a frame 11 of generally i -shaped configuration and the forked ends of frame 11 respectively support a pair of upstanding bearing plates 14. A pair of stub axles 12 are horizontally secured to plates 14 and such axles rotatably mount transporting of end portion 27a.

- wheels 13. Such plates-also support atransverse tubular shaft 15 and such shaft in turn rotatably mounts a sub,-

stantially quadrant shaped hopper 16. Hopper 16 con 7 tains the material to be distributed by material distributor it). A transversely extending endless belt 17 is mounted in hopper 16 for longitudinal movement. The endless belt 17 is mounted on a pair of longitudinally spaced rollers 18, such rollers being spaced apart by a pair of arms '19, respectively provided at opposite ends of rollers '18 as best shown in Fig. 2. Alongitudinal tube member 2'1 hasits ends respectively welded to 'a medial portion of each of the arms 19 to transversely space such arms at opposite ends of belt 17. The rearwardly disposed roller 18 is rotatably mounted on an axis coincident with the apex of the quadrant shaped hopper 16 as best shown in 5 Fig. 2.

A control device 21 including an hydraulically operated ram is mounted on the lefthand forked portion of frame 16 as shown in Figs. land 2 and the pump of such control device, to be-later described, is driven by a sprocket '22. Sprocket 22 is connected by a chain 23 to a sprocket 24 mounted'on the axle 12 adjacent the left hand wheel with respect .to the axis of shaft 34. The eccentric cylindrical portion 34a lies within the hollow interior ofthe arcuately shaped end portion 27a of housing 27 as shown in Figs. 3 and 6. Eccentric 34a is'utilized to actuate a pump piston as will be .later explained. A sprocket 22 is secured to a projecting end of shaft 34 by a key 22a. Key 22a is locked in place bya radial screw 22b. A pair of oil sealing rings 35 are provided about shaft 34 adjacent the ends thereof within suitable annular rings 34b.

Near the upper edge of housing 27 there is provided a longitudinally disposed, cylindrical bore 27g which communicates with the hollow interior of the arcuate end portion 27a of housing 27. A cylindrical piston-like member 36 is inserted in bore 27g and such piston memberslidably cooperates with the wall of bore 27g. The

' right hand end of piston member 36.contacts the eccen- '13 as shown in Figsll and 2. Chain 23 likewise surrounds at sprocket 25 secured on the left h'and'end .of the rearmost roller 18, thus sprocket 24 driven by ground I Wheel 13 'moves chain ;23 to rotate sprocket 22 and sprocket 25 sprocket25 in turn effects rotation of the endless bel-t- 17. The endless belt inturn scrapes ma terial from the top of the material contained in hopper 1 6 and forces such material on the right hand end of hopper id as shown in Fig. 2, whereupon such material falls by gravity to strike a deflecting plate "26 provided across the rear end of hopper 16 whereupon the material fall to the ground.

The control device 21 for gradually rotating hopper v:16 comprises a cast housing 2.7 of'generally rectangular configuration as besttshown in Figs. 3 and 6. Housing 27 has a depending integrally cast cylindrical portion '28 ;-which projects somewhat beyond each end of housing 27 as shown in Fig. ,3. The housing 27 has an arcuately shaped right hand end 27a which projects upwardly somewhat above the main portion of the housing 27. The interior of housing 27 and the arcuate end portion 27a of such housing are hollow as shown at 27b and is so formed by coring. The'cylindrical portion28 of housing 27 is provided with an axial bore v28a 'which'slidably receives a piston 29. On the right hand end of cylinldrical portion 28 as shown inFig. 3, there is provided an integral depending boss 285 while on the left hand end there is provided a forwardly extending depending lug 28c. Boss 28b has a verticahcylindrical threaded recess-28d whereby the rear'end of housing 27 is secured to frame ll'by a bolt 3%, bolt 3i) passes through the flange of frame 11 and threadably engages recesses 28d. A

bolt-31 inserted througha suitable vertical aperture in the flange :of frame 11 aligned with a vertical hole 282' provided in' lug 28c, fastens the forward .end of housing 27 to frame 11.

On the left handside of the arcuate end portion 27a 7 of housing 27 as shown in Fig. 6 there is provided a cylindrical boss 27c while on opposite side of housing end portion 27a there is provided a boss 27d of substantially larger diameter. An axial hole 27c is provided in boss 27; which communicates with the hollow interior A cylindrical cover 31 fits over the end of boss 27d and such cover is secured to boss -27d by a plurality of bolts' 32, a gasket'33 being placed between the adjacent surfaces of cover 31 and lug 27a. Cover 31 hasan integral, inwardly projecting bearing boss 31a and such boss has B os-s 27d has anp ax ial hole 2.7;! '-and the axes of the bores 27 and 272 are coincident; 7

tric 34a as best shown in Fig. 3. Alfiuid pressure regulator indicated generally bythe numeral 37 is slidably inserted in bore 27g behind piston member 36.

The fluid regulator 37 comprises a cylindrical housing 37a which has an axial cylindrical recess 37b provided in the right hand end thereof as shown in Fig. 7.- Re cess 37b has an endxre-ces's 370 of smaller diameter and formed coaxially therewith. A third recess 370? is provided at the end of recess 37c and such recess is. also co-axial with recess 370. A ball check valve 38 is suitably'sea-ted in the bottom of recess 370 to block ofi recess 37d. Ball 38 is spring biased into place by a spring 38a which is retained in position by a suitable retainer 33b suitably secured in an angular groove provided in'recess 37c. p

To admit hydraulic fluid to recess 37d 21 diametrically disposed hole '37e is provided at the bottom of recess 37d. *A wide annular groove 37f isprovided about the exterior of housing 37 which communicates with a vertical hole 27f that is provided infhous'ing 27 which in turn communicates with alongitudinal hole 2711 provided near the bottom of housing 27 and immediately above the cylindrical portion 28 as shown in V-Fig. 3. Hole 27h likewise communicates with the hollow interior 27b of housing-27 which serves as an hydraulic fluid reservoir. A vertically disposed hole 271' provided on top of arcuately shaped end-27a of housing 27 permits filling theinterior 27b with hydraulic fluid and such hole is sealed by a threaded plug 4t V V A threaded shaft 41 projects outwardly'from the regulator 37 and such shaft may be either integrally formed therewith or secured in suitable fashion an axial recess provided in the left hand end of regulator 37. Threaded shaft 41 cooperates with a threaded hole i421: provided in an upstanding bracket 4 -2. Bracket 42 con1 prises a bar-like member and is vertically secured by a pair of bolts 42b to the left hand end of housing 27 as shown in Fig. 3. A suitable knob or handle 431's non-rotatably secured to the end .of shaft41 projecting beyond bracketAZ whereby threaded shaft 41 may be rotated. It Will then be appreciated that regulator 37 will be'likewiserot ated but will'also be moved longitudinally within bore 27g whereby such regulator may be withdrawn from bore 27g or further inserted therein de pending upon the direction of rotationIof shaft 41.

In the forward end 'ofthe'recess. 37b of regulator 37, there i inserted a bushingfl3 andsuch bushing has an axialjhole 43a which supports the end of a plunger 44. Plunger 44 has ahead. portion44a which slidablycoopcrates with the wallof recess;,37b and: such head portion also is provided with a conical surfacefl id adjacent the stem which cooperates with a conical rece'ss 43b provided on the inside edge oftbushing 43 for. limiting the travel ofsuch plunger. as ,willbje, later explained.

fl' he right 'hand. end of plunger 44 contacts the. end of piston member 36'. Asp ring 45 jis placed within recess plunger 44 will be later described.

Piston 29 is slidably contained within longitudinal bore 28a and a piston rod 2% is axially secured to piston 29 by a nut 29!) screwed on to a threaded end of piston rod 29a which projects through piston 29. An oil sealing ring 29c disposed in an annular groove 2%! provided on the peripheral face of such piston effects improved oil scalin The extreme left end of bore 28:: is conically enlarged as shown at 28f to permit pressured fluid to escape from bore 28a as will be later described.

The extreme left end of bore 281? is ccunterbored as shown at 233. Such counterbore corn unicates with longitudinal hole 271i whereby hydraulic nuid from bore 28a may escape or return to the reservoir 27b. Counterbore 23g is sealed by a cap 46 and such cap is secured to the end of the cylindrical portion 23 of housing 27 by a plurality of bolts $612, a gasket 4-515 being placed between such cover and the end of cylindrical portion 23. The right hand of piston rod 2% is axially supported within bore 284: by a bearim plug 47. The right hand end of bore is counterbored as shown at 23k to receive such pin". A split ring 43 cooperates with a suitable ann' "r groove provided in the wall of counterbore r 'n plug 47 therein. Bearing plug 47 has an axial hole 4% which slidably supports piston rod right end of hole 4% is counterbored as Sill in at 47b, in which is placed a suitable packing to effect an oil seal about the piston rod 29a projecting out or" counterbore 475. A clevis 58 is secured on the end of pist n rod 29a which projects out of bearing plug 47 and such clevis is locked on the end of piston rod 29a by a jam nut 59a.

The eccentric 34a provided on shaft 34- is rotated by sprocket 22. Sprocket 22 in turn is driven by the chain 23 which surrounds the ground wheel driven sprocket 24. Accordingly as eccentric 34a is rotated, piston member 3d, contacted by eccentric Sin, is forced inwardly w.-

recess 27g by such eccentric. The spring iased plunger 44 being in contact with the other end of piston member 36 however, tcrces piston member 36 outwardly a whereupon such piston member is again contacted by such eccentric on its next revolution hence a reciprocating action is imparted to piston member 35. Accordingly when piston 3s moves to the right as shown in 3, hydraulic fluid from reservoir M712 is drawn from such reservoir through vertical hole 271' to annular groove 37 thence through hole 3% of regulator 37. Such fluid then flows past ball check valve 38, which is opened by the suction stroke of piston 36, thence flows along the longitudinal grooves 445 of head 44a, and 440 provided on the stem of plunger 44 and into the space defined between the end or" regulator 37 and piston 36.

On the compression stroke of piston 36, that is when such piston c /ed to the left as shown in Fig. 3 by the eccentric a, spring biased ball check valve 33 automatically seals oil the fiuid from returning to the reservoir so that the hydraulic fluid pressured by the compression movement of the piston so is forced out through a transverse hole 551 (Fig. 4} which communicates with bore 27g at a point opposite the extreme end of the compression stroke of piston 36. Transverse hole 51 is counter-bored shown at 51a and a ball check valve 52 is seated in such counterbore, Ball check valve is yieldingly retained insealing position by a spring 52a and such spring is retained in counterbore 51a by a threaded plug 53 which is screwed into the threaded entering end of counterbore 51a. Hole 51 communicates with a downwardly sloping bore 54 which communicates with the right hand end of bore 28a in the vicinity of the end of bearing plug 47 (not shown). Thus pressured hydraulic fluid enters the bore 28a to act against the face of piston 29.

It will be appreciated that each stroke of piston 36 forces a slug of hydraulic fluid against the face of piston 2% hence such piston is moved incrementally for each compression stroke of piston 36. Thus the output of the pump, that is each stroke or" the piston 36, is proportional to each revolution of eccentric 34a and the output is infinitely variable by axial positioning of regulator 37.

if at any time it is desired to bleed the hydraulic fluid contained in bore 28a back to the reservoir to return the element being moved by piston rod 2911, it is merely necessary to open a transverse port 55 provided in housing 2'7 which communicates with hole 54 and reservoir 27b, Transverse hole 55 is counterbored as shown at and a ball check valve 56 is seated therein which normally blocks off hole 55. A spring 57 yieldingly holds checl; valve 56 in its seated position. A threaded plug 53 retains spring 57 within counterbore 55a. Ball check valve 56 is removed from its seat by a pin 59 to permit fluid to flow from bore 28a into reservoir 27b. Pin 59 has a reduced diameter end 5922 which fits within hole 55. Such end is fluted to permit hydraulic fluid to flow past such reduced diameter nd when the ball check valve 55 is unseat-ed as will be presently explained. The other end of pin 59 has a threaded portion 5% which cooperates with a transverse threaded hole 6% provided in the other sic or" housing 27 in axial alignment with hole 55. An integral boss 27;: (Fig. 4) is provided on the exterior of housing 27 co-axial with hole 6% through which such hole passes. Hole 6b in boss 27p, however, is counter'oored as shown at dt'ia to receive an enlarged diameter portion 5% of pin 59. A knob 5% is provided on the end of pin 59 projecting out of boss 66 whereby pin 59 may be rotated to advance or retract the end portion 59a of such pin out of hole 55 whereby ball check valve 56 may be unseated to permit hydraulic fluid to return to reservoir 27b.

The control device 21 is utilized to rotate hopper 16 at a rate proportional to the ground speed of the device so that the material contained in such hopper will be constantly engaged by the endless belt 17 in order to deposit such material on the ground at a constant rate of delivery per unit of area traversed. Accordingly, there is provided on the left hand end of hopper 16 as shown in Figs. 1 and 2, a quadrant shaped cable guide 61. Such guide is secured to the end of hopper 16 as by welding and one end of a cable 62 is secured to the top of hopper 15 as by a hook 16c. Cable 62 is trained around quadrant member 61 and the other end is suitably secured to clevis 5%.

Operation To raise hopper 16 at a controlled rate of speed proportional to the ground speed of ground wheel 13, the control device 21 is automatically operated when the fertilizer distributor is towed along over the ground, driving sprocket 24 efiecting rotation of sprocket 22 through the chain 23. in the position of hopper 16 as shown in Fig. 2, piston rod 29a extends out of bore 28a so that piston 29 abuts the inside face of bearing plug 47. Rotation of sprocket 22 drives shaft 34 and in turn rotates eccentric 34a which reciprocates piston member so, the inward stroke serving to compress the hydraulic fluid drawn into recess 37b on the outward stroke of piston 36 as was previously explained. The pressured fiuid then escapes through hole 51 and forces open ball check valve 52 so that the pressured fiuid flows along hole 54 to enter the extreme right hand end of bore 28a.

As the amount of pressured fluid is incrementally built up in cylinder 28, the piston 2? is incrementally moved to the left and piston rod 2% is then drawn into bore 28:: pulling therewith cable 62. Hence as cable 62 is attached at 16a to hopper 16, the hopper will then be hydraulic incrementally rotated. in a clockwise direction.- As. long as the ground speed of implement 1% is constanhn constant how of pressured fluid will be forced into bore 28a to act against the face of piston 29 to move piston 29a incrementally inwardly at a substantially uniform rate of speed. Thus a constant rate of delivery of material will be delivered by endless belt'l'l'. However, in the event that the ground speed of the implement 16 increases or.

decreases, the eccentric 3 5:: will correspondingly increase or decrease in speed to vary the rate of flow of pressured fluid into cylinder 28. Obviously there Wlll be a corresponding increase or decrease in the rate or" movement of hopper 1 6 relative to the variable ground speed of the implement. Thus even with variations in the rate of speed of the implement, a constan delivery of material by endless belt 17 will be assured.

To provide for a greater or lesser delivery of material by belt 17, the rate of rotation of hopper 16 may be readily varied by the pressured fiuid regulator 37. When regulator 37 is in the position shown in Fig. 3, piston 36 can then reciprocate through its maximum stroke.

that shown in such figure, the plunger 44 is biased to the right by spring 45 whereupon piston 36 will be forced to move to the right an amount equal to the maximum throw of eccentric 34a. Obviously when the eccentric rotates another 180 degrees, the piston 36 will be moved in the opposite direction back to the position shown in On the compression stroke ofsuch piston, as I Fig. 3.

when the piston moves towards the left as shown in Fig.3, the column of oil ahead o'fthe piston defined by As the eccentric 34a rotates approximately 180 degrees from Press red fl id cont ined in o e-lflaiis. per itted in.

escapethrqughhole SSQ'into reservoir ZZhasthe weight of, hopper (.16 noted ..up.on by gravity, withdraws piston rod 291: out ofthehorezsa thereby moving piston 29to the extreme right handfend of suchbore and into contact with the end of bearing plug 47. h

From the abovedescription it is clearly apparent that there is, here provideda control device which is particularly useful in controlling. the rotation of the hopper of a material distributingdevice. Such control device can be conveniently set to vary 'the rate of travel of the hopper whereby a greater or lesser amountvof material 7 may be distributed by the material distributor. i It is also apparent that this cohtrol devicepermits a constant rate of deliverysof material by the material distributor regardless or the ground speed of the distributor as the rate of delivery is a function of theground speed, Furthermore, the device may be conveniently and accurately set to provide for any rate of delivery of material so that an d vantage and without guess-work.

the space between the left hand ei d face of piston 36. V

and bushing 43 is then forced through opening 51 thence into the cylindrical bore 28a. With each suction stroke of piston 36, spring biased plunger 44 forces piston 36 to the right so that such piston will be contacted by some The length of peripheral portion of eccentric 34a. stroke of piston 36 is dependent upon the axial position of regulator 37. At the extreme right hand position of 4-40 of plunger 44 will fit thereby limiting further piston 36 the conical portion within the conical recess 43b movement of plunger 44.

As regulator 37 is withdrawn from recess conical recess 43b of bushing 43 will likewise be moved a corresponding amount, thus the axial position of plunger 44 will also be changed an amount correspondingv to the movement of such regulator. Thus the length of stroke .of piston 36 on the suction strok'e will be reduced an amount equal Obviously therefore, any reduction in the length of stroke to the movement of regulator 37.

or piston '36 reduces the amount of oil forced into cylindrical bore 28a thus reducing the amount of travel of piston 29 and hence producing acorresponding reduction 7 in the rate of movement of hopper 16.

It is readily apparent that an infinite number of settings of regulator 37 is readily obtainablelpy rotation of knob 43, thus the strokeof piston 36 can be adjusted to provide but a minute flow of oil to cylindricalbore 28:: whereby the. movement of piston 29 is barely perceptible. l-Ience it is possible by means of this adjusting device to provide a wide range of movement of piston 29 so that infinitely variable rates of material discharge from the hopper l may be obtained regardless of the ground speed of the material distributor. I

When the hopper is rotated to its upper extreme position, piston 29 then reaches the end of its stroke in bore 2822 thereby uncovering the tapered conical portion 28f of bore 28:: whereby pressured'fiuid contained in bore 28a may escape by piston '29 and return to the reservoir 27b through hole 27h, thus the possibility of damage to the control device 21 is substantially eliminated. Hopper 16 may at any time be readily returned to the position shown in Fig. 2; for reloading or other reason bybleeding the i pressured 'fluid contained in bore 128a through apertureJS'S'byrotating pin '59 to'unsearvalve 56. Thus'the the unskilled operator can utilize this device to It will, of course, be understood that various details of construction may be varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent ing a compression stroke only to said pump piston, a

piston regulator in said bore constructed and arranged for axial movement therein, a spring pressed plunger in said regulator, said plunger being in contact with said pump piston for imparting a suction stroke to said pump piston, a fluid reservoir, first fluid passage means for withdrawing fluid from said reservoir into said bore on said suction stroke, second fluid passage means for delivering fluid from said bore to said cylinder on the com 7 pression stroke of said pump piston for delivery to said cylinder, and means for varying the axial position of said regulator in said bore to vary the effective stroke of said pump piston by limiting the suction stroke imparted thereto by said plunger, whereby said hopper is incrementally pivoted as a function of the travel of said ground wheel.

2. For use with a material distributor having apivoted hopper; a control device comprising, in combination, a fluid pressure ram, means connecting the ram to the pivoted'hopper to pivot the same, a pump having a reciprocable piston movable through a pressure stroke and a return stroke, means for driving the piston in its pressure strokeionly, fluid conduit means connecting the pump and the ram, a piston follower, means urging said follower towards the piston to move said piston in its return stroke, and stop means adjustable longitudinally of said piston to limit movement of the follower and to limit movement of the piston in its return stroke, thereby varying theincremental quantify of fluid supplied by said piston to said ram and controlling the rapidity with which said ram pivots said hopper.

3. For use with amaterial distributor having a pivoted hopper; a control device comprising, in combination,,a fluid pressure ram, means connecting the ram to the pivoted hopper to pivot the same, a pump housing having a fluid reservoir, said housing also defining a bore, a pump piston in said bore, means in said pump housing for imparting only. a .compression stroke to said pump piston, a pump piston regulator in said bo'reconstructed and arranged rm. axial movement therein and having the best admeans for lay-passing fluid therepast to said pump piston, a spring pressed plunger in said regulator, said plunger being in contact with said pump piston and spring pressed thereagainst for imparting a suction stroke to said pump piston, first fluid passage means for withdrawing fluid from said reservoir and past said regulator into said bore on said suction stroke, second fluid passage means for delivering fluid from said bore to said ram on the compression stroke of said pump piston, and means for varying the axial position of said regulator in said bore to vary the effective stroke of said pump piston to thereby vary the incremental quantity of fluid supplied by said pump piston to said ram and control the rapidity with which said ram pivots said hopper.

References Cited in the file of this patent UNITED STATES PATENTS 617,135 Weeks Jan. 3, 1899 1,996,723 Henneuse Apr. 2, 1935 2,131,749 Ofeldt Oct. 4, 1938 2,286,888 Arnold June 16, 1942 2,407,104 Schmied Sept. 3, 1946 2,430,197 Wells et a1. Nov. 4, 1947 

